Reliability-based evaluation of steel structures using energy concepts

A procedure for the structural assessment of the preliminary design of earthquake-resisting structures has been proposed. The reliability-based procedure takes into account explicitly the maximum and cumulative plastic deformation demands in the earthquake-resistant structure. Particularly, the procedure verifies that the structure has the capability to control and accommodate the maximum demands of global ductility, interstory drift and dissipated hysteretic energy (hysteretic energy dissipated through plastic deformation), through the use of: (A) Constant maximum ductility strength spectra and constant normalized dissipated hysteretic energy strength spectra with uniform annual failure rates; and (B) Transformation factors that take into account the differences between the response of multi-degree-of-freedom and single-degree-of-freedom systems. The use of the procedure, which is applicable to regular ductile steel frames that are designed according to the concepts of capacity design, is illustrated through its application to the structural revision of the preliminary design of an 8-story steel frame.